USB portable power supply



FIG. 1 is a perspective view of a USB portable power supply showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side view thereof; and,

FIG. 5 is a right side view thereof. 

CLAIM The ornamental design for a USB portable power supply, as shown and described. 